docs: def _get_cols(row_content):
      """
      Counting the number columns based on the content of this row
      """
      cols = []
      subcell_col = []
      prev_bar = None
      for _coord, item in row_content:
          if isinstance(item, LTTextLine):
              subcell_col.append(item)
          else:  # bar, add column content
              # When there is no content, we count a None column
              if prev_bar:
                  bar_ranges = (prev_bar, item)
                  col_items = subcell_col if subcell_col else [None]
                  cols.extend([bar_ranges, col_items])
              prev_bar = item
              subcell_col = []
      # Remove extra column before first bar
      return cols